Al-Kāfi - Volume 5 > Buying and Selling Food
Hadith #6

6- مُحَمَّدُ بْنُ يَحْيَى عَنْ مُحَمَّدِ بْنِ الْحُسَيْنِ عَنْ صَفْوَانَ بْنِ يَحْيَى عَنْ إِسْحَاقَ بْنِ عَمَّارٍ عَنْ أَبِي الْعُطَارِدِ قَالَ قُلْتُ لأبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) أَشْتَرِي الطَّعَامَ فَأَضَعُ فِي أَوَّلِهِ وَأَرْبَحُ فِي آخِرِهِ فَأَسْأَلُ صَاحِبِي أَنْ يَحُطَّ عَنِّي فِي كُلِّ كُرٍّ كَذَا وَكَذَا فَقَالَ هَذَا لا خَيْرَ فِيهِ وَلَكِنْ يَحُطُّ عَنْكَ جُمْلَةً قُلْتُ فَإِنْ حَطَّ عَنِّي أَكْثَرَ مِمَّا وَضِعْتُ قَالَ لا بَأْسَ بِهِ قُلْتُ فَأُخْرِجُ الْكُرَّ وَالْكُرَّيْنِ فَيَقُولُ الرَّجُلُ أَعْطِنِيهِ بِكَيْلِكَ فَقَالَ إِذَا ائْتَمَنَكَ فَلَيْسَ بِهِ بَأْسٌ.

6. Muhammad ibn Yahya has narrated from Muhammad ibn al-Husayn from Safwan ibn Yahya from Ishaq ibn ‘Ammar from abu al-‘Atarud who has said the following: “I once said to abu ‘Abd Allah, ‘Alayhi al-Salam, that I buy food in a deal in the beginning of which I lose and in the end I gain profit. I then ask my friend to reduce a certain amount on each kur. He (the Imam) said, ‘There is nothing good in it, however, he can reduce a certain sum.’ I then asked, ‘Can he reduce more than I have lost?’ He (the Imam) said, ‘It is not harmful.’ I then asked if I can keep aside one or two kur and the man asks me to give him according to my measurement. He (the Imam) said, ‘It is not harmful if he can trust you.’”